Competitions

# Complex numbers: addition and subtraction

Two complex numbers are given. Find their sum or difference.

#### Input

Each line contains an example of addition or subtraction of complex numbers. The complex number is given in the format a+bi or a-bi, where a is integer, b is non-negative integer. The real and imaginary part of each complex number is no more than 109 by absolute value.

#### Output

For each input example, print in a separate line the answer.

Time limit 1 second
Memory limit 128 MiB
Input example #1
2+3i + 7-4i
12-4i - 5-4i
-1-1i - -1-1i
5-2i - -7+12i

Output example #1
9-1i
7+0i
0+0i
12-14i

Author Michael Medvedev